Methods of preparing partially dried or essentially completely dried compositions comprising microfibrillated cellulose and an inorganic particulate material may include microfibrillating a fibrous substrate comprising cellulose in an aqueous environment by grinding in the presence of an inorganic particulate material to form an aqueous composition comprising microfibrillated cellulose and inorganic particulate material, wherein the fibrous substrate comprising cellulose has a Canadian Standard freeness equal to or less than 450 cm, wherein the fibrous substrate to the inorganic particulate material are in a ratio of about 99.5:0.5 to about 0.5:99.5, and wherein the microfibrillated cellulose has a fibre steepness of from about 20 to about 50; by treating the aqueous composition comprising microfibrillated cellulose and inorganic particulate material to remove at least a portion or substantially all of the water of the aqueous composition to form a partially dried or essentially completely dried composition comprising microfibrillated cellulose and inorganic particulate material.